New Jersey Governor Chris Christie points as he delivers the keynote address to delegates during the second day of the Republican National Convention in Tampa, Florida, August 28, 2012. REUTERS/Eric Thayer

"We can get this country working again. We can get this economy growing again. We can make the safety net safe again. We can do this," Ryan told cheering delegates at the GOP convention Wednesday night. "Whatever your political party, let's come together for the sake of our country. Join Mitt Romney and me."

Amid the applause for Ryan was the sound of the future. The Republican Party's next-generation leaders were in ample supply at the GOP's convention as they positioned for national roles and, perhaps, even their own shot at the White House in four or eight years.

After victories at all levels of government in the past few years, the GOP has a deep bench of up-and-coming governors, senators and, it seems, even House candidates. It's diverse, too, for a party that faces serious demographic challenges — particularly among Hispanics — in a country that's becoming more multicultural by the day.

"Growing up, I never imagined a girl from a border town could one day become a governor. But this is America," said New Mexico Gov. Susana Martinez, the nation's first Latina governor.

Condoleezza Rice, the first black female secretary of state, reminded delegates that she had grown up in the segregated South. "My parents taught me to never give up," she said, "and to always believe that my future could be whatever I dreamt it to be."

"In 2020, someone that you see speaking in a prominent role today is probably going to be on the ballot," said Lew Oliver, a Florida delegate from Orlando.

The Republican marquee represents "the emerging faces of the conservative cause," said former Florida Gov. Jeb Bush, a potential future presidential candidate — like many others in attendance. He made the comment this week as he sat between Martinez and another first-term governor, Brian Sandoval of Nevada. Both are Hispanic, and talked about often in GOP circles as the future of the party.

Should Romney win in November, Ryan automatically would be considered the next leading prospect for the GOP nomination. Other Republicans on the rise could find themselves in the new administration. Some could end up being key political allies in presidential battleground states. And others could emerge as intellectual leaders within the party.

A Romney loss this fall to President Barack Obama would — perhaps as soon as the day after the election — set off a mad scramble among countless Republicans to emerge as the next presidential nominee.

Among those considered likely to weigh a run:

—Ryan, the Wisconsin congressman and federal budget specialist who will have had one national political campaign under his belt. His relative youth may serve as a bridge between generations, as he noted in his speech when he wryly compared his iPod playlist to Romney's: "I hope it's not a deal-breaker, Mitt, but my playlist starts with AC/DC and ends with Zeppelin."

—Christie, the New Jersey governor, who delivered a rousing keynote address Tuesday night and last year decided against a 2012 run.

—Bush, the oldest son of President George H.W. Bush and brother of President George W. Bush, who has long rejected overtures to run.

—Rubio, the Florida senator and Cuban-American who has spent the past year working to boost his national political profile.

There are countless others talked about — and they, too, were on hand.

New Hampshire Sen. Kelly Ayotte, South Dakota Sen. John Thune and Virginia Gov. Bob McDonnell all received polite receptions. Rice, a party favorite, was buzzed about as she sat in the Romney family's private box and later addressed the delegates.

Wisconsin Gov. Scott Walker, who gained national attention for his fight against his state's public employee unions and for defeating a recall effort, delivered a robust speech in which he said that Romney, like himself, understands that "people, not the government, create jobs."

"Now, more than ever, we need reformers ... leaders who think more about the next generation than just the next election," Walker said. "That's what you get from Mitt Romney and Paul Ryan."

Christie's blunt, brash personality was on display during his keynote address as he implored: "Everybody stand up. There's no time left to waste."

South Carolina Gov. Nikki Haley, an Indian-American, drew hearty applause when she criticized Obama's challenge to her state's new immigration law. It requires police who have stopped someone for unrelated issues to report it if they suspect the person is in the country illegally.

"If this president refuses to protect our borders, refuses to protect our citizens from the dangers of illegal immigration, then states have to take it upon ourselves," she said.

Rubio was slated to introduce Romney on Thursday and gave a preview of his speech while at a salsa concert Monday night.

"There's no community that understands how to grow an economy faster than Americans of Hispanic descent," Rubio said. "We're as entrepreneurial, as hardworking as any people in this country and at the end of the week it will be clear to all of America that there's only one person running for president that understands what it takes to grow the economy and that's Mitt Romney."

The deep roster excites rank-and-file Republicans about the future.

"I see wins, wins, wins," said Denise Graves, a delegate from Linden, Mich.

Allen Alley, chairman of the Oregon Republican Party, said he was excited about hearing some of the new GOP stars that he hadn't seen before, saying, "The country will be introduced to a Republican Party that they have not been aware of."